Air flow capture system

ABSTRACT

An apparatus and kit for capturing airflow from an inlet of a centrifugal fan, the centrifugal fan having a housing containing an impeller rotatable about a fan axis and an inlet passing through the housing along the centrifugal fan axis, the apparatus comprising a frame securable to the centrifugal fan housing across the centrifugal fan inlet and a capture fan rotatably supported by the frame, the capture fan having a center of rotation about the centrifugal fan axis. The apparatus further comprises an electrical generator motor operably connected to and drive by rotation of the capture fan, wherein the capture fan is rotatable in a first direction about the centrifugal fan axis by air drawn into the centrifugal fan inlet during operation of the centrifugal fan. The kit further comprises a centrifugal fan.

BACKGROUND OF THE INVENTION 1. Field of Invention

The present invention relates generally to the field of energy capturesystems, and in particular to an air flow energy capture system.

2. Description of Related Art

Furnace and air circulation systems most commonly employ centrifugalfans, also known as squirrel cage fans or blowers, to draw air into thesystem and to move the air through at a constant speed. Air is drawninto the fan through an inlet in the side of the housing, then turns 90degrees and is accelerated with centrifugal force as it passes over thefan blades and exits the fan through an outlet in the housing. As air isdrawn into the fan through the inlet, the air increases in speed,creating a draft at the inlet, both within and outside of the fanhousing.

SUMMARY OF THE INVENTION

According to a first embodiment of the present invention there isdisclosed a apparatus for capturing airflow from an inlet of a fan theapparatus comprising a capture fan located upstream of the centrifugalfan and an electrical generator motor operably connected to and drive byrotation of the capture fan wherein the capture fan is rotatable in afirst direction by air drawn into the fan inlet during operation of thefan. The capture fan may be located in a cabinet wall surrounding thefan.

The fan may comprise a centrifugal fan, the centrifugal fan having ahousing containing an impeller rotatable about a fan axis and an inletpassing through the housing along the centrifugal fan axis, theapparatus may further comprise a frame securable to the centrifugal fanhousing across the centrifugal fan inlet. The capture fan may berotatably supported by the frame wherein the capture fan has a center ofrotation about the centrifugal fan axis and wherein the capture fan maybe rotatable in a first direction about the centrifugal fan axis by airdrawn into the centrifugal fan inlet during operation of the centrifugalfan.

The capture fan may comprise an axial fan having a central hub and aplurality of fan blades extending radially therefrom. The plurality offan blades of the axial fan may comprise radial fan blades extendingradially outward from the hub to a tip region. Each of the plurality offan blades may have a leading and a trailing edge. The leading edge maybe convex. The trailing edge may be concave. The tip region of theradial fan blades may be secured to a cylindrical outer band. Each ofthe plurality of fan blades may be skewed rearwardly from the leadingedge to the trailing edge.

According to a further embodiment of the present invention there isdisclosed a fan system for capturing airflow comprising a powered fan, acapture fan located upstream of the powered fan and an electricalgenerator motor operably connected to and drive by rotation of thecapture fan wherein the capture fan is rotatable in a first direction byair drawn into the fan inlet during operation of the powered fan. Thecapture fan is located within a cabinet wall of a cabinet containing thepowered fan.

The powered fan may comprise a centrifugal fan having a centrifugal fanhousing wherein the fan system may further comprise a frame adapted tospan an inlet in the centrifugal fan housing and securable to thecentrifugal fan housing. The capture fan may have a center of rotationabout a capture fan axis at the capture fan center, the capture fanrotatably mounted to the frame wherein the capture fan may be rotatablein a first direction about the capture fan axis by air drawn into theinlet during operation of the centrifugal fan.

The capture fan may comprise an axial fan having a hub at the capturefan center and a plurality of fan blades. The plurality of fan blades ofthe axial fan may comprise radial fan blades extending radially outwardfrom the hub to a tip region. The tip region of the radial fan bladesmay be secured to a cylindrical outer band.

Other aspects and features of the present invention will become apparentto those ordinarily skilled in the art upon review of the followingdescription of specific embodiments of the invention in conjunction withthe accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings which illustrate embodiments of the invention whereinsimilar characters of reference denote corresponding parts in each view,

FIG. 1 is a perspective view of an airflow capture system installed on acentrifugal fan according to a first embodiment of the presentinvention.

FIG. 2 is an exploded view of the airflow capture system of FIG. 1.

FIG. 3 is a top view of an axial fan.

FIG. 4 is a perspective view of fan casing having an airflow capturesystem installed therein.

FIG. 5 is a perspective view of a capture fan for use in the system ofFIG. 1 according to a further embodiment.

FIG. 6 is a plan view of the capture fan of FIG. 5.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, an apparatus for capturing airflow from aninlet of a centrifugal fan according to a first embodiment of theinvention is shown generally at 10. The apparatus 10 is mounted to acentrifugal fan 8 over an inlet 6, as will be set out below.

The apparatus 10 comprises an electrical generator motor 12 mounted to aframe 30 and coupled to an axial capture fan 50 along a central axis100. The frame 30 is mounted to the centrifugal fan 8 over the inlet 6.

Referring to FIG. 2, the frame 30 comprises an L-bracket 32 mountedwithin a center ring portion 34 with a plurality of elongate supportarms 36 extending radially outwards from the center ring portion 34 todistal ends 38. The L-bracket 32 and support arms 36 may be secured tothe center ring portion 34 by any known means, such as, by way ofnon-limiting example, welding. The L-bracket 32 may include a pluralityof mounting holes 40 therethrough along spaced apart axes perpendicularto the central axis 100, adapted to allow the electrical generator motor12 to be mounted thereto, as will be further set out below.

As illustrated, four support arms 36 extend in an x-shape from thecenter ring portion 34, although it will be appreciated that more orless support arms 36 may be useful, as well. A mounting hole 42 extendsalong an axis spaced apart and parallel to the central axis 100 througheach support arm 36 proximate to the distal end 38. The length of thesupport arms 36 is selected such that the frame 30 spans across theinlet 6 of the centrifugal fan 8 with the mounting holes 42 aligned withmatching mounting holes 44 on the centrifugal fan 8.

The electrical generator motor 12 includes mounting feet 14, asillustrated in FIG. 2. A driveshaft 16 with external threading 18thereon extends outwards from the center of the electrical generatormotor 12 along a driveshaft axis 102. The mounting feet 14 are securedto the frame 30 by any means as is commonly known, such as, by way ofnon-limiting example, a plurality of welds, nuts and/or bolts throughthe mounting holes 40. In the mounted position, the driveshaft axis 102and central axis 100 are aligned such that the driveshaft 16 extendsalong the central axis 100. As is commonly known in the art, theelectrical generator motor 12 includes a generator wire 20 extendingtherefrom, through which electrical power is supplied to other sources,such as, by way of non-limiting example, a charge controller 22 orrectifier.

Turning to FIGS. 2 and 3, the axial capture fan 50, extending between afront and rear, 80 and 82, respectively, comprises a central circularhub 52 with a plurality of fan blades 54 and a cylindrical outer ring56. As best seen on FIG. 2, the hub 52 includes a central circularportion 70 at the front 80 with a cylindrical wall portion 72 extendingaxially from the central circular portion 70 at the front 80 to the rear82, along the central axis 100. The hub 52 includes an aperture 58extending through the circular portion 70 at the center to allow thedriveshaft 16 to extend therethrough for rotation about the central axis100 in a first rotation direction 104. The outer ring 56 encloses thefan blades 54 and is generally centered on the central axis 100.

Each fan blade 54 extends radially between a root region 60 secured tothe cylindrical wall portion 72 of the hub 52 and a tip region 62secured to the outer ring 56. The fan blades 54 are joined to thecylindrical wall portion 72 of the hub 52 at the root region 60 over thefull width of each blade and are joined to the outer ring 56 at the tipregion 62 over the full width of each blade. Each fan blade 54 includesa convex leading edge 64 and a concave trailing edge 66. As best seen inFIG. 2, the leading edge 64 at the root region 60 is secured to thecylindrical wall portion 72 proximate to the front 80 of the fan, withthe root region 60 skewed rearwardly such that the trailing edge 66 issecured to the cylindrical wall portion 72 proximate to the rear 82 ofthe fan. Similarly, the tip region 62 of each fan blade 54 is secured tothe outer ring 56 such that the leading edge 64 is proximate to thefront 80 of the fan and the trailing edge 66 is proximate to the rear 82of the fan. This style of fan design is commonly known and often used inthe automotive industry for cooling purposes.

To assemble the apparatus 10, the electrical generator motor 12 issecured to the frame 30 as outlined above. The frame 30 is secured tothe centrifugal fan 8 with fasteners 98 through the mounting holes 42and 44. The fasteners 98 may be of any suitable type, such as, by way ofnon-limiting example, screws or nuts and bolts. A threaded coupling 90with internal threading adapted to engage the external threading 18 onthe driveshaft 16 is coupled to the driveshaft 16 and to a fastener 92through the aperture 58 in the axial capture fan 50, thereby securingthe axial capture fan 50 to the driveshaft 16 of the electricalgenerator motor 12. The fastener 92 includes external threading 94adapted to engage with the internal threading of the treading coupling90 and includes a head portion 96 sized to span the aperture 58 andengage upon the circular portion 70 of the hub 52.

Referring to FIG. 1, when the centrifugal fan 8 is in operation, air ispulled into the inlet 6 of the centrifugal fan 8 in a directiongenerally indicated at 106. As air is pulled into the centrifugal fan 8,the axial capture fan 50 rotates in the first rotation direction 104,thereby rotating the driveshaft 16 of the electrical generator motor 12and producing electrical power.

Turning now to FIG. 4, alternatively, the capture fan 50 may be locatedin a cabinet wall 202 of a fan cabinet containing the centrifugal fans8. As illustrated in FIG. 4, cabinet 200 may contain more than onecentrifugal fan 8 and more than one capture fan 50. It will beappreciated that the cabinet 200 may include an access port 204 coveredby a door which is not illustrated in FIG. 4 so as to illustrate theinterior of the cabinet 200.

Turning now to FIGS. 5 and 6, an illustration of a second side of acapture fan 300 for use in the present system according to a furtherembodiment is illustrated. As depicted, the capture fan includes a hub302 having a hub channel 304 extending therethrough and a fan bladeassembly housing 306. The fan blade assembly housing 306 may be securedto the hub 302 with bolts 308 or the like as are commonly known.

In some embodiments, the fan blade assembly housing 306 has an innerdiameter 320 of about 6 inches. In some embodiments, the fan bladeassembly housing 306 has an inner diameter 320 between about 4 inchesand 8 inches. In some embodiments, a fan hub 302 has a diameter 330 ofabout 11 inches. In some embodiments, a fan hub 302 has a diameter 330between about 8 inches and 20 inches. In some embodiments, the width 340of the plurality of first fan blades 310 is about 5⅞ inches. In someembodiments, the width 314 of the plurality of first fan blades 122 isbetween about 4 inches 10 inches. In some embodiments, the first fanblade assembly 300 has a diameter 350 of about 23 inches. In someembodiments, the first fan blade assembly 300 has a diameter 350 betweenabout 18 inches and 24 inches.

As illustrated, the first side of a first fan blade assembly 300 has aclockwise rotation of 322, and each first fan blades 310 has a fan bladetailing edge 312 and a fan blade leading edge 314 with a pitch angle ofabout 40 degrees and 9 fan blades. In some embodiments, each fan blades310 has a fan blade tailing edge 312 and a fan blade leading edge 314with a pitch angle between about 20 degrees and 60 degrees and betweenabout 4 and 20 first fan blades. In some embodiments, the verticalbetween the fan blade tailing edge 312 and the fan blade leading edge314 is about 2¼ inches. In some embodiments, the vertical between thefan blade tailing edge 312 and the fan blade leading edge 314 is betweenabout 1½ inches and 10 inches. The fan blade assembly 300 may beselected to be an automotive radiator cooling fan.

While specific embodiments of the invention have been described andillustrated, such embodiments should be considered illustrative of theinvention only and not as limiting the invention as construed inaccordance with the accompanying claims.

What is claimed is:
 1. An apparatus for capturing airflow from an inletof a fan the apparatus comprising: a capture fan located upstream ofsaid centrifugal fan, an electrical generator motor operably connectedto and drive by rotation of said capture fan; wherein said capture fanis rotatable in a first direction by air drawn into said fan inletduring operation of said fan.
 2. The apparatus of claim 1 wherein saidcapture fan is located in a cabinet wall surrounding said fan.
 3. Theapparatus of claim 1 wherein said fan comprises a centrifugal fan, thecentrifugal fan having a housing containing an impeller rotatable abouta fan axis and an inlet passing through the housing along thecentrifugal fan axis, the apparatus further comprising: a framesecurable to said centrifugal fan housing across said centrifugal faninlet, wherein said capture fan is rotatably supported by said frame,said capture fan having a center of rotation about the centrifugal fanaxis; and wherein said capture fan is rotatable in a first directionabout said centrifugal fan axis by air drawn into said centrifugal faninlet during operation of said centrifugal fan.
 4. The apparatus ofclaim 3 wherein said capture fan comprises an axial fan having a centralhub and a plurality of fan blades extending radially therefrom.
 5. Theapparatus of claim 4 wherein said plurality of fan blades of said axialfan comprise radial fan blades extending radially outward from said hubto a tip region.
 6. The apparatus of claim 5 wherein each of saidplurality of fan blades has a leading and a trailing edge.
 7. Theapparatus of claim 6 wherein said leading edge is convex.
 8. Theapparatus of claim 6 wherein said trailing edge is concave.
 9. Theapparatus of claim 5 wherein said tip region of said radial fan bladesare secured to a cylindrical outer band.
 10. The apparatus of claim 4wherein each of said plurality of fan blades is skewed rearwardly fromsaid leading edge to said trailing edge.
 11. A fan system for capturingairflow comprising: a powered fan; a capture fan located upstream ofsaid powered fan, an electrical generator motor operably connected toand drive by rotation of said capture fan; wherein said capture fan isrotatable in a first direction by air drawn into said fan inlet duringoperation of said powered fan.
 12. The fan system of claim 11 whereinsaid capture fan is located within a cabinet wall of a cabinetcontaining said powered fan.
 13. The fan system of claim 11 wherein saidpowered fan comprises a centrifugal fan having a centrifugal fanhousing, the fan system further comprising: a frame adapted to span aninlet in said centrifugal fan housing and securable to said centrifugalfan housing, wherein said capture fan has a center of rotation about acapture fan axis at the capture fan center, said capture fan rotatablymounted to said frame. wherein said capture fan is rotatable in a firstdirection about said capture fan axis by air drawn into said inletduring operation of said centrifugal fan.
 14. The apparatus of claim 13wherein said capture fan comprises an axial fan having a hub at saidcapture fan center and a plurality of fan blades.
 15. The apparatus ofclaim 14 wherein said plurality of fan blades of said axial fan compriseradial fan blades extending radially outward from said hub to a tipregion.
 16. The apparatus of claim 15 wherein said tip region of saidradial fan blades are secured to a cylindrical outer band.